The present invention relates to a flat electric heater element, in particular for heating a small region of a glass pane of a motor vehicle.
EP 1 281 574 B1 discloses a flat electric heater element for heating a mirror of a motor vehicle. Two current conductor layers and one electrical resistance layer are formed on a carrier film as the heater element. The resistance layer extends between the two current conductor layers and is in electric contact with both of them. The flat heater element has an unobstructed, light-diffusing area for the light of a signal indicator. The electrical resistance layer is composed of a material with a positive temperature coefficient (PTC). The electrical resistance of the said material is temperature-dependent. It increases as the temperature rises and decreases as the temperature falls.
The object of the invention is to provide a way of reducing the risk of signal transmission defects, which can be caused by snow, ice or condensation water, for electrical signaling devices, which communicate with external devices, in motor vehicles, even when only a small amount of installation space is available in the motor vehicle.